Unit Economics describes the revenue and costs associated with a single unit of business (customer, transaction, delivery), determining whether a model is fundamentally profitable or structurally doomed.

Why It Matters

Growth without profitable unit economics = burning money faster toward death. Many startups achieved “escape velocity” illusion—revenue grew, losses grew faster. Unit economics revealed truth: does acquiring/serving one more customer make or lose money?

Core Calculations

Customer Unit Economics:

• Revenue per customer (LTV)
• Cost to acquire customer (CAC)
• Cost to service customer (COGS, support)
• Gross margin per customer

Transaction Unit Economics (Marketplaces):

• Revenue per transaction (take rate × GMV)
• Cost per transaction (payment processing, fraud, support)
• Contribution margin

Real-World Examples

Uber/Lyft (2015-2020): Negative unit economics for years. Lost $2-5 per ride after driver subsidies, insurance, fraud, support. Betting on autonomous vehicles or market dominance to fix.

MoviePass (2017-2019): $9.95/month, paid theaters $12-15 per movie. Every active user lost money. Burned $21M/month, collapsed spectacularly.

DoorDash (2018-2022): Lost money per delivery 2018-2020 (delivery fees < driver pay + support + fraud). Achieved positive unit economics 2021 via: higher fees, lower driver pay, reduced fraud, increased order sizes.

Shopify (2015-2023): Strong positive unit economics. $29-$299/month plans, minimal COGS (software scales free), gross margins 75%+.

Marketplace Challenge

Two-sided marketplaces (Uber, Airbnb, DoorDash) subsidized both sides early to achieve liquidity. Unit economics negative for years by design—betting network effects would flip profitability once scale achieved. Many never flipped (WeWork, MoviePass), few did (Airbnb profitable 2017, DoorDash 2021).

Contribution Margin

Key metric: revenue minus variable costs = contribution margin. Positive contribution margin meant each unit contributed to fixed costs. Negative meant every sale lost money—only path to profitability was raising prices or cutting costs to flip unit economics.

2021 ZIRP Era Sins

Zero interest rates enabled ignoring unit economics—VCs funded “grow now, profit later.” Companies with -50% contribution margins raised billions. 2022-2023 correction forced reckoning: path to profitability = fixing unit economics or dying.

Source: a16z Unit Economics Guide